Tortum Lake

Tortum Lake is a natural landslide-dammed lake located within the boundaries of the Uzundere district in Erzurum Province, in Eastern Anatolia, Türkiye. Situated in the transition zone between the Black Sea and Eastern Anatolia regions, the lake is of natural origin, both in terms of its geological formation and environmental characteristics. Tortum Lake extends approximately 8.2 kilometers in length and 1.4 kilometers in width along a southwest-northeast axis and lies at an elevation of 1010 meters above sea level. With a maximum depth of 95 meters, its surface area is about 6.5 km². At normal water level, the lake’s volume is 57.6 hm³.

Formation and Geological Structure

Tortum Lake was formed at the end of the 17th century (approximately 350–370 years ago) when a massive landslide from Kemerli Mountain blocked the Tortum Creek valley. The waters accumulating behind this natural dam formed the lake, while excess water flowed northward through the Tev Valley to create Tortum Waterfall. The main body of the lake consists of landslide materials, while its shoreline and underlying structure are composed of Jurassic-Cretaceous clayey limestones, sandstones, and volcanic rocks. The physical properties of these rock formations significantly influence sedimentation processes around the lake.

Geomorphological and Hydrographic Characteristics

The lake lies within a basin enclosed by steep and narrow valleys between Mescit Mountain (3230 m) and Kargapazarı Mountain (3045 m). Due to sediments carried by Tortum Creek, the lake is subject to active sedimentation from the southwest. A large delta has developed between the Cizirik and Beşkardeşler hills, where annual accumulation of 3,695,106 tons of suspended sediment and 596,000 tons of coarse sediment has been recorded. This process leads to a reduction in the lake’s volume and a gradual shift of the shoreline toward the lake center. The majority of sediment transport occurs via tributaries such as Bağlar, Vihink, Hınzorik, Liskav, and Mususin streams in the upper catchment area of the lake.

Climate and Ecological Structure

Tortum Lake lies in a transitional zone between the humid climate of the Black Sea region and the continental climate of Eastern Anatolia. In Uzundere, the average annual temperature is 9.29 °C and the average precipitation is 307.7 mm; in Tortum, these values are 8.19 °C and 468.7 mm respectively. Spring snowmelt increases streamflow and intensifies sediment transport. The surrounding area supports forested regions with species such as pine, oak, and juniper, while lower elevations feature steppe and Mediterranean-type plant communities.

Natural Threats and Conservation Status

Tortum Lake faces environmental threats from overgrazing, illegal logging, and sand and gravel quarries. Uncontrolled sediment accumulation alters the lake’s morphological structure, erodes the shoreline, reduces biodiversity, and endangers its hydroelectric, recreational, and ecological functions. For these reasons, the lake and its surroundings were declared a Class I Natural Site in 2000, and its protected boundaries were expanded in 2002 to enhance conservation efforts.

Human Activities and Hydroelectric Power Generation

The lake was integrated into energy production with the completion of the 26 MW Tortum Hydroelectric Power Plant in 1960. In 1971–1972, a 1.5-meter-high and 35-meter-long concrete dam was constructed at the lake’s outlet to regulate water flow. A portion of the lake’s water is also diverted to feed Tortum Waterfall. Settlements, small-scale agricultural areas, and picnic zones are located around the lake.

Legends of Tortum Lake and Waterfall

Rich folk traditions surround Tortum Lake and Tortum Waterfall, interpreting their natural formation through local beliefs and preserving them as integral elements of regional cultural identity. Below are the principal examples of these legends:

The Story of “Tortum,” the Most Beautiful Girl

According to the most widespread legend, the name Tortum derives from a remarkably beautiful girl. It is said that this young woman, named Tortum and the daughter of the Ağcakale Bey, gained fame throughout the region for her beauty. Despite prolonged requests, her family refused to give her to the bey’s son, who had fallen in love with her. One day, a brave young man disguised as a merchant arrived in Üngüzek, brought gifts, abducted the girl, and took her to the bey’s son. Shortly after their marriage, the young woman fell ill and died from sorrow and longing. Before her death, she bequeathed that her name be given to the land. Thus, the region came to be called “Tortum.”

The Shepherd Who Heard a Whisper

In another folk tale, a shepherd from Hars (Uludağ) village in Uzundere heard a voice saying “Geliremm” three nights in a row while tending his flock. Finally, he consulted the village elders, who advised him to respond on the fourth night with: “Come then, what will you do?” As soon as he spoke these words, a portion of the mountain broke loose and blocked the course of Tortum Creek, forming Tortum Lake, while the overflow created Tortum Waterfall.

The Voice “Get Out, I’m Coming!” and the Disappearance of Hasköy

In another version, a beautiful girl living in the wealthy village of Hasköy at the foot of Kemerli Mountain would go every night to fetch water from the stream. One night, she heard a voice cry “Get out, I’m coming!” and replied, “Come then, what will happen?” Immediately after her reply, a landslide detached from the mountain and swallowed the village, forming the lake and the waterfall.

The Shepherd and the Greedy Lord Legend

In this legend, a shepherd grazing his animals on the mountain noticed a rock slowly shifting from its place. He reported the danger to the village lord, but the lord dismissed his warning. One day, the mountain collapsed with a great roar onto the village, killing everyone except a few who were outside. When it became clear that the shepherd had been telling the truth, the cruel lord, who had previously tormented him, burst into rage and died. This event is linked to the lake’s formation.

The Warning “Get Out, Get Out!” and the Tale of Salvation

According to this account, a shepherd sleeping while tending his flock on the mountain had a dream in which he heard the warning “Get out, get out!” Upon waking, he told the villagers, but no one believed him. The shepherd took his flock and left the village. The next day, a major earthquake struck and the village was buried beneath the mountain. The resulting landslide formed Tortum Lake, and the flowing water created Tortum Waterfall.